This invention relates generally to machine tools and in particular to a boring bar adjusting apparatus for automatically measuring the diameter of a hole produced by the boring in the spindle of the machine tool and automatically adjusting the boring bar if the hole is not within tolerances.
Many of the boring operations completed on workpieces produced in manufacturing facilities are performed by computer numerically controlled (CNC) machining centers. Often, such machining centers include an automatic tool changer which transfers tools between the machine tool storage magazine and the machine tool spindle without the need for manual intervention. Such automatic tool changing machine centers not only increase production, but also reduce direct labor costs.
To achieve relatively high production, while still affording the flexibility of manufacturing different types of parts, manufacturing cells, and flexible manufacturing systems have been developed utilizing machining centers that are interconnected by way of a workpiece transfer or shuttle mechanism. In such manufacturing cells and flexible manufacturing systems, once the part has been machined, the part is usually inspected to assure that the part meets manufacturing tolerances. Such inspection can be accomplished at the machine tool, by way of a spindle probe, but more often, part inspection generally occurs at a separate inspection station, which may include one or more automatic inspection devices. If, during the inspection process, the part does not meet manufacturing tolerance, such as may occur when a workpiece bore is slightly undersized, by virtue of having been machined by a worn cutting tool, then the part is diverted for subsequent machining. In large manufacturing facilities the diversion of parts to be remachined often creates a logistics difficulty which may seriously impede part production.
In an effort to overcome this difficulty, the present invention is directed to an automatic boring bar adjustment apparatus for a machine tool. The invention provides for measuring the hole produced by the boring bar and automatically adjusting the boring bar to compensate for any error in the diameter of the hole and then reboring the hole to the proper diameter.